1) Abash 2) Addle 3) Agitate 4) Faze 5) Getto 6) Rattle 7) Ruffle 8) Throwoffbalance 9) Unsettle 10) Worry 1) Agitate 2) Be flustered 3) Befuddle 4) Behave in a confused manner 5) Bewilder & unnerve 6) Bewilder %26 unnerve 7) Cause to be nervous or upset 8) Confuse 9) Discombobulate 10) Discomposure 11) Perturbation 12) Psych out 13) To be agitated and confused 14) To be in a heat or bustle 15) To confuse 
• (v. i.) To be in a heat or bustle; to be agitated and confused. • (n.) Heat or glow, as from drinking; agitation mingled with confusion; disorder. • (v. t.) To make hot and rosy, as with drinking; to heat; hence, to throw into agitation and confusion; to confuse; to muddle.
Flus'ter intransitive verb To be in a heat or bustle; to be agitated and confused. « The flstering , vainglorious Greeks.» South. Flus'ter noun Heat or glow, as from drinking; agitation mingled with confusion; disorder. Flus'ter transitive verb [ imperfect & past participle Flustered ; present participle & verbal noun Flustering .] [ Confer Icelandic flaustra to be flustered, flaustr a fluster.] To make hot and rosy, as with drinking; to he...
make nervous or confused 
[v] - be flustered 2. [v] - cause to be nervous or upset
verb cause to be nervous or upset
to put into a state of agitated confusion: His constant criticism flustered me. · to excite and confuse with drink.
[SAT terms] cause to be nervous or upset